1. Field of the Invention
The present invention relates to a liquid recovering apparatus for use in recovering outflow oil such as crude oil, scum in sewage disposal plants, food producing plants and so on, coolant oil in machining centers, floating oil in grease removal processes for plating and so on.
2. Description of the Prior Art
In recent years, there have occurred a number of ocean polluting accidents due to outflowing crude oil or combustible oil caused by the stranding, sinking and so on of ships, particularly, tankers. It has therefore been strongly desired to recover such outflowing oil as much as possible to achieve preservation of the environment.
A variety of apparatuses for recovering outflow oil have been developed to respond to such requests, and Japanese Patent Publication No. 53-26422 (1) issued to the present assignee has been known. The present assignee has also filed Japanese Patent Applications Nos. 3-123712(2) and 4-16771 (3) . The techniques described in these documents will be explained below.
In known Japanese Patent Publication No. 53-26422, an oil accumulating chamber is arranged on an upper portion of a separator in a bath at a level higher than the liquid surface for recovering oil by means of a vacuum pump. Water is separated and sent to an overflow tube arranged in an internal vessel and discharged by a discharging pump.
In Japanese Patent Application No. 3-123712 by the present assignee, liquid including low specific gravity oil and so on entering from an inlet port of an inflow guide enters from an inlet port of a bath into the inside thereof and is impeded from passing by obstructive plates, whereby oil and other components are separated by the difference in specific gravity, and the oil is accumulated in a separator bath. When a predetermined amount of liquid is accumulated, oil is recovered from an extracting tube, water enters an internal tube from a separator, flows into an overflow tube and is once isolated. Then, the water in the overflow tube alone is discharged to the outside.
Japanese Patent Application No. 4-16771 by the present assignee adjusts a fixing position of a guide float of an inflow guide to freely set the level of a guide inflow gate. Further, a fixing position of a main body float provided for a main body bath may also be adjusted to freely set the level of a main body inflow gate. In this way, clots of oil, scum and so on can be relatively easily recovered by adjusting the levels of the guide and main body inflow gates in accordance with a quantity of such clots and scum. Specifically, if there are many clots of oil, the levels of these gates may be set to be low.
The prior art examples (1) and (2) described above are both adapted to efficiently recover only oil and therefore are convenient for the case where oil slick is prevented from extending by an oil fence or the like which surrounds oil on the water surface. However, they are complicated in structure, limited in the processing capability, and too large to bring with ease, so that they tend to delay attending to an urgent case. Specifically, these prior art examples are not sufficient to recover as fast as possible oil slick, which is going to extend on the water surface, so as to prevent the oil slick from extending.
Further, these apparatuses cannot recover clots of highly viscous oil and scum which does not smoothly path through the inlet port, or these clots and scum may block the inlet port, which results in hindering the apparatus from recovering liquid including oil.
Although the prior art example (3) can recover liquid even including clots of oil, scum or the like by adjusting the level of a guide inflow gate, clots of oil having a viscosity above a predetermined value, excessively grown scum and so on does not smoothly pass through the inlet port and therefore cannot be recovered. Further, the adjustment of the fixing position of the guide float for adjusting the level of the guide inflow gate must be made for all guide floats provided in the apparatus. Therefore, this apparatus requires an excessive amount of manipulation particularly when applied to the recovery of floating oil in grease removal process for plating which requires frequent adjustments of the level of numerous guide inflow gates.